CTO Equity Question

Hey guys. I’m pretty new to the equity and vesting side of startups so I had a question.

So I may be joining a small startup as their CTO. The current team is only 2 people and they have been running the startup “manually” since they started. I offered to build a web app for them and if they liked it, I would join as the CTO. Well the web app is done and they are ready for me to join.

They sent an equity consideration of 25%. 0.5% which I would get now for handing over the MVP. The rest is vested over 4 years (12.5%,12.5%,25%,50%).

My question is if this is reasonable. Recently they told me they want to pivot away from providing the “manual” service and make the software the product and turn it into a SaaS. If the software is going to the forefront of the company, is this a good deal? I have no idea what kind of vesting plan they are on and not sure if it’s appropriate to ask. Any help would be appreciated!